Interoception Flashcards
What is interoception?
The sense of the internal state of the body.
Foundation of sense of the physical self.
What does Interoception tell us?
- The feelings we receive from the body
- Homeostasis
- Informs us of our physical state
What is the restrictive definition of interoception?
Purely visceral - info concerning the functional state of the internal organs
What is the inclusive definition of interoception?
General homeostatic sensory capacity - info concerning the broader physiological state and motivational needs of the body
What is the goal of homeostasis?
To achieve physical equilibrium
What pathway do intereoceptive signals follow?
Neural anatomical pathway
What is the anatomical pathway?
Similar categories of afferent nerves.
What kind of pathway is the neural anatomical pathway?
Ascending.
Consisting of afferent neurons (nerve fibers carrying info towards the brain)
What are afferent neurons?
Carrying signals from the body to the brain
How does myelination effect the neurons in the anatomical pathway?
- Increases efficiency of electrical transmission (signals travel faster)
What information do myelinated nerves carry?
Nociceptors (pain)
What information do unmyelinated nerves carry?
Affective touch (CT afferents)
Where do interoceptive signals travel in the spinal cord?
- Into the dorsal horn of the spinal cord
- The cells in the dorsal horn are divided into physiologically distinct layers (laminae)
- Projects contralaterally to the lateral spinothalamic tract
Where do interoceptive signals travel in the brain?
- Lamina 1 projects to brain stem
- Then to the thalamus, hypothalamus and amygdala
- Finally to the cortex (specifically insula and anterior cingulate)
How do afferent projections maintain homeostasis?
- Afferent projections from the dorsal horn provide the somato-automatic reflexes crucial for maintaining homeostasis
- Continuous feedbackk
What is another name for the insula cortex?
The interospective cortex
Where is the insula cortex?
Hidden in the centre of the brain
How is interoception linked to emotions?
- There’s an intrinsic link between the physiological state of the body and emotion
- Emotions can be felt in the body
What is alexithymia?
People have no words for their emotions - linked to interoception deficits.
Explain our ‘gut feeling’ using interoception.
- The interconnection between the gut and the brain is deeply rooted in our language
- Neural network communicates with the brain about gastrointestinal homeostasis.
- Bidirectional - emotions can influence digestive system too
Where did Aristotle believe the self was?
In the heart
Where is the self?
The strongest sensations we get in our bodies is usually related to the heart.
But we live in a very thought-led society so the self could also be in the head/brain.
How can interoception affect behaviour?
- Emotional behaviours evolved to produce goal-directed actions that fulfil homeostatic needs of the body
- How you feel can be moderated by physiological state of the body
- How you feel can influence your behaviour
How do physiological motivations effect our behaviour?
- Cognition takes place within the context of the body that needs to stay alive and be healthy
- Brains evolved to regulate bodies within a social context
Give an example of how phsyiological motivations effect our behaviour?
Piece of cake - at first the piece of cake looks yummy but once you’ve eaten it, your body tells you that you’re full and so you don’t eat anymore before you are sick.
Explain the link between interoception and behaviour.
- Affective experience influenced by the current body state
- Drives behaviour to achieve homeostasis
What paradigm did Garfinkel et al 2014 study?
Attentional Blink (AB) Paradigm
What happens in the Attentional Blink Paradigm?
Identification of an initial target during a rapid serial visual presentation of stimuli which impairs the ability to detect the second target.
What did Garfinel et al 2014 measure against the rapid serial visual presentation?
Different phases of the heartbeat - Systole and Diastole states
What is systole?
When the heart contracts
What is diastole?
When the heart relaxes
What are Baroreceptors?
Thin, myelinated neurons that go into the spinal cord to convey info from the heart to lead the brain to cause top-down regulatory signals to come back to that homeostatic state of equilibrium
What did Garfinkel et al 2014 do in the second half of their experiment?
Target 1 was always a house and Target 2 was a face (disgust, fear, sad, happy, or neutral).
Following the AB task, the recognition od T1 and T2 stimuli was examined
What did Garfinkel et al 2014 find?
- Timing of stimuli facilitated detection of T2 for fear faces only.
- Systole presentation led to greater proportion of fear faces being detected.
What did Garfinkel et al 2014 do in their second experiment?
- MRI experiment
- Neutral of fear faces presented briefly
- Presented in either diastole or systole
- Emotion intensity ratings
What did Garfinkel et al 2014 find in their second experiment?
- Timing of the stimuli related to intensity judgments
- Systole stimuli led to greater intensity for fear faces
0 Diastole stimuli trend for greater intensity for neutral faces
How did Garfinkel et al 2014’s experiment link to anxiety?
They found that the interaction between the cardiac cycle and the emotion intensity seemed to be related to their state level of anxiety.
What did MRI scans show in Garfinkel et al 2014’s second experiment?
- Cardiac presentation i slinked to anterior insular activity
- Amygdala activity is sensitive to phases of the cardiac cycle and predicted shifts in emotion
How can Garfinkel et al 2014’s results be translated in the real world?
- Percdeption of threat is dependent on the level of physiological arousal
- In systole, the heart is working the hardest
- Greater arousal (more and stronger heartbeats) would mean more time in systole compared to diastole
What did Azevedo et al 2017 study?
- Complex human behaviours
- Effect of cardiac cycle on racial stereotyping
- Comparing stimulus presentation in systole and diastole
What was the method in Azevedo et al 2017?
- Identify targets (tool or weapon)
- Primed by black or white male faces
- presented at systole or diastole
- PP was asked to identify whether the second stimulus was a weapon or tool
What did Azevedo et al 2017 find?
- More correctly identifying weapons when primed with a black face is systole
- More correctly identifying tools when primed with a white face in systole
- Basically systole exacerbated racially steretyped responses
What was Azevedo et al 2017’s second study?
First Person Shooter Task
What was the method of Azevedo et al 2017’s second study?
- PPs were police
- Had to decide whether or not to shoot the criminal
- Confederated were either armed or unarmed and either black or white
What did Azevedo et al 2017 find in their second study?
- PPs chose to shoot unarmed black men more often than unarmed white men
- Significant effect is again only found during systole and in the unarmed condition
- Important on how the physiological state of the body effects both emotions and thus our behaviour
What is Interoceptive Accuracy?
How accurate an individual is at detecting and interpreting interoceptive signals when compared with objective measures
How do we monitor heartbeat?
- Mechanoreceptors respond to mechanical stimuli
- Coronary mechanoreceptors detect changes in arterial blood pressure and generate afferent signals on each heartbeat
- Individuals with high mechanoreceptive sensitivity may be able to feel and count their own heartbearts
How do you take part in the heartbeat counting task?
- participant counts heartbeats felt during a brief timeframe
- actual heartbeats measures (ECG, pulse transducer)
- Relate counted heartbeats with actual heartbeats
What is Interoceptive Sensibility?
The subjective experience of interoception - how interoceptive signals are experienced irrespective of their objective reality.
What is MAIA?
Multidimensional Assessment of Interoceptive Awareness
What is Interoceptive Awareness?
The correspondence between objective interoceptive accuracy and subjective reports
- A metacognitive awareness of one’s own interoceptive accuracy
What happens in the brain when attending to our heartrate?
Greater activation in the anterior insula when detecting a mismatch between the notes and heartbeats
What correlates with accuracy of heartbeat detection?
- Insula activity
- Grey matter volume
What is the insular cortex associated with?
- Cognitive and emotional tasks
- Body-related tasks
Where is the insular cortex?
Hidden cortex folded below the lateral sulcus.
Beneath opercula of the frontal, parietal and temporal lobes.
Where is the posterior connectivity in the insular cortex?
Posterior thalamus
Where is the anterior connectivity in the insular cortex?
Limbic system, amygdala
What connectivity is in the middle zone of the insular cortex?
Mix of anterior and posterior connectivity
What is the connective route in the insular cortex?
Input enters the posterior insula and then connected to the mid and anterior for integration with other modalities
What information does the insular cortex receive?
Info about blood pressure and oxygenation, the timing and strength of the heartbeat etc.
What top down control happens in the insular cortex?
Top-down control of autonomic functions such as the regulating the heartbeat and blood pressure
What other processes is the insular cortex involved in?
- Pain
- Emotion
- Cognition
- Social
- Subjective feeling states
What part of the insular is used in interoception?
Posterior insula
What part of the insula is used in exteroception?
Anterior insula
What is the mid-insula responsive to?
- Hedonic (pleasant) response to food
What can deficits in insular activity lead to?
Maladaptive thoughts and behaviour (e.g. panic disorder)
How are psychiatric disorders related to interoception?
- Interoceptive symptoms are prominent features of many psychiatic disorders e.g. anxiety and eating disorders
What could be the interoceptive deficits causing psychiatric disorders?
- Different processing on interoceptive signals
- Bias in reporting interoceptive signals
What is corporeal awareness?
The perception, knowledge and evaluation of one’s own body as well as of other bodies
What are interoceptive states constructed from?
Information from sensory predictions and regulatory actions
What do classic theories suggest about interoception?
That cortical regions either reflect stimulus intensity or additive effects of intensity and expectations
What do predictive theories suggest about interoception?
That perception is shaped by the integration of beliefs about the world with mismatches resulting from the comparison of these beliefs against sensory input
What is an inaugural moment?
Initial sensory map from the body without prior experience
How do we experience body state?
- Predicted body state continually updated from afferent information and cognition
- Results in prediction errors
- Small errors ignored
- Large errors detected and regulated to maintain homeostasis
- Adapt predictions or adap physiological state
How do anatomical connections link to anxiety?
- Allow integration pf physiological state and cognition
- Linked to 2 key components of anxiety: sympathetic hyperarousal and worry
What did Gueter et al 2014 find?
- Posterior insular exhibited neural patterns in line with detecting pain intensity - receives afferents from viscerra
- Anterior insula exhibited neural patterns in line with predictive coding of pain - integrates info with other modalities
- these predictions are modality specific
What did Gueter et al 2014 find?
- Posterior insular exhibited neural patterns in line with detecting pain intensity - receives afferents from viscerra
- Anterior insula exhibited neural patterns in line with predictive coding of pain - integrates info with other modalities
- these predictions are modality specific
What is a social phobia?
Exaggerated fear of negative scrutiny in social interactions
What is a specific phobia?
Irrational fear of something that poses little or no actual danger
What is PTSD?
Anxiety and flashbacks triggered by a traumatic event
What did Etkin et al 2007 find about phobias/PTSD/anxiety?
Patients with all disorders demonstrate hyperactivity in the amygdala and insula
What are maladaptive behaviours?
E.g. avoidance, withdrawal
What are maladaptive cognitions?
e.g. rumination, worry
What is a somatic error?
Overall difference between the predicted and observed body state
What is panic disorder?
Regular sudden attacks of panic or fear
What is a panic attack?
Sudden onset of interoceptive signals associated with fear/panic: dizziness, dyspnea, palpitations. feeling of impending doom or death
Compare the insula in healthy participants compared to those with panic disorder.
Panic disorder: increased grey matter volume in the insula
How do those with panic disorder get into a vicious cycle?
- Experience mismatch between actual and experiences bodily state but then regulate body to minimise mismatch - increased heart rates - further anxiety
How does belief affect interoception?
- Change in the internal state which may be due to increases attentional bias toward the threat
- Beliefs used to interpret internal body signals
- External cues or internal thought generate anticipation of aversive body states that sets up body prediction error
Which part of the brain is guilt linked to?
Left anterior insular cortex
Which part of the brain is linked to sad self-relevant autobiographical memories?
Ventral insular
What is the somatic error hypothesis?
Psychiatric disorders may be a result of mismatches between anticipated and incoming bodily signals
What is compensatory behaviour in the somatic error hypothesis?
Psychiatric sympomology
What is our experience based on?
- Future predictions
- Past experiences
- Current inputs
What is anorexia nervosa?
- Extreme overvaluation of shape and weight
- Disturbed eating, resulting in clinically significant impairments and psychosocial function due to self-starvation
- Resistance to treatment, poor prognosis, high mortality
How is interoception linked to AN?
- Intuitive link between interoception and hunger
- dysfunctional thoughts and feelings impacting the interpretation of visceal signals
How do patients with AN perform on the heartbeat perception task?
Reduction in the ability to accurately perceive their heartbeat compared to healthy controls
What is the issue of cause and effect in AN studies?
- Starving causes a lot of physical symptoms so it’s difficult to know
- But there was no link to BMI in blood pressure studies so people who are more emaciated did not have a worse effect than they suggest - more to do with the pathology and then a consequence to starvation
How is interoceptive accuracy and sensibility training effective in AN patients?
Any recovery was small and inconsistent
Where are the most interoceptive deficits in AN?
Focussed on the gastric system
What is rumination?
process of continuously thinking about the same thoughts, which tend to be sad or dark
What happens in the insular in AN patients during stomach interception?
Reduced activity in the dorsal mid-insular
What happens in the insula in AN patients during heart interception?
Higher activity in anterior insula
What happens in the insula in AN patients during anxious rumination?
Increased activation in the dorsal mid-insular
How are patients with AN led into a vicious interoceptive cycle?
- Abnormal stomach interoception might worsen gastrointestinal symptoms during weight restoration
- Gastric discomfort leading to anxiety and then greater discomfort
What is isoproterenol?
Adrenoreceptor agonist or saline
What happens to AN patients before consuming a meal?
Intense cardiorespiratory
What prevents intuitive eating in AN patients?
- Abnormal mapping of interoceptive signals results in prediction errors in internal body
- Intuitive link between difficult perceiving hunger and satiety and dysfunctional eating habits
How does interoception affect body image in AN patients?
- failure to update external perception of the body
- don’t realise they have lost weight and continue to feel dissatisfied
How does interoception lead to relapse in AN patients?
- Prediction errors may lead to further errors and negative affective that is unresolved
- Lead to risk of relapse
- Both exteroceptive and interoceptive bodily symptoms continue following weight restoration
How does interoception and treatment work together in AN patients?
- Interoceptive abnormalities seem resistant to treatments
- Plasticity of the insula suggests issues can be targets for treatment
What is the neural anatomical pathway?
- Small-diameter afferent nerves project to Lamina 1 of the dorsal horn of the spinal cord
- Projects contralateral to the lateral spinothalamic tract
- Terminates in the posterior insula cortex
what modalities of interoception are there?
- gastrointestinal
- nociceptive (pain)
- thermoregulatory
- cardiovascular
What practical issues are there with measuring heartbeat as a measure of interception?
- People tend to guess at roughly 1 per second
- Gender
- Individual differences
What practical issues are there with measuring heartbeat as a measure of interception?
- People tend to guess at roughly 1 per second
- Gender
- Individual differences
